The power of dams

Hydro is the top source of renewable electricity in Europe, but environmentalists are concerned about the proliferation of new projects.

Thanks to its dams, the European Union is expected to meet its goal of deriving 20% of its energy from renewable sources by 2020, vs. 16.4% in 2015. Hydropower was the second most important contributor to the renewable energy mix in 2014 (16.5%), behind solid biofuels and renewable waste (63.1%).

Most dams with a capacity above 10 MW were built before 2000. “Dams of that size are too controversial now”, said Jippe Hoogeveen of the Food and Agriculture Organization. As a result, new structures tend to be smaller and located in Eastern Europe, where there is untapped potential. The industry is investing at a current annual rate of €8 billion to €12 billion; projected spending could reach €180 billion by 2030.

Hydropower is prized for its flexibility. Pumped-storage, which makes up two-thirds of Europe’s hydro, is a system that stores water when electrical demand is low and uses it to generate power when demand is high. It is the only large-scale, competitive form of electrical storage currently available

Asia in the lead

Europe’s 10 most powerful dams

The Sayano–Shushenskaya dam in Russia can produce as much energy as six nuclear power plants. Switzerland’s Grande Dixence can provide electricity to 400,000 households.

Europe’s largest

Large hydroelectric dams More than 15 m high, or 5-15 m high with a reservoir of more than 3 million m³. Dams mapped to nearest town with varying precision. Data points may overlap.

The race is on

Europe has 23,000 dams, of which more than 2,000 are large, active hydroelectric structures. In the Balkans, close to 2,700 new dams are planned – mainly small and medium-sized. Environmental organisations challenge the notion that smaller dams are friendlier than large ones. “The environmental consequences are the same, regardless of size, and small dams do not produce much electricity at all”, says Cornelia Wieser of the Austrian organisation Riverwatch. “The 21,000 small dams make up 91% of the total, but they generate only 13% of all hydropower.”

Sources: Aquastat, World Bank, European Commission, Euronatur, European Environment Agency, Eurostat, Fluvius, ICOLD, International Energy Agency, International Hydropower Association, Riverwatch, The Guardian, World Energy Council